Dr Tom Dolphin, of the BMA's junior doctors committee, added: "There has been appalling confusion in the NHS over the last few weeks."

Dr Matt Jameson Evans, a spokesman for Remedy UK, said: "There is likely to be widespread problems, particularly in trusts where the fill-rate is low.

"The whole process has been a disaster from start to finish."

However, the government remains confident any disruption will be kept to a minimum.

Deputy Chief Medical Officer Professor Martin Marshall said: "We know that August is always a quiet month with fewer outpatient appointments and fewer operations, which is why the junior doctor rotation happens at this time every year.

"The numbers involved will be higher this time, but NHS trusts are used to dealing with this issue and have plans in place to make sure services run properly during August."